So it looks like I have Blue Green Algae- Can you help me figure out why?

[summit]

I have bright green patches growing across my aquarium gravel, it seems to be spreading quite quick, and its like slime, I can only assume its the dreaded BGA, I am hoping you can help me why I got it in the first place, and maybe help me get rid of it.

Little bit of background my tank is an 8 gallon, with 3 stage filtration built into the hood, 23 watt fluorecent lighting 10 hours on 14 hours off, fluorite black substrate, driftwood, and an amazon sword, fully cycled and its current inhabitants are 3 neons 1 cardinal neon and an otto cat.

Nitrates have never gone over 10, ammonia and nitrites are 0, I do weekly water changes of about 30%, one area of suspect is I think my tank has a relitively low water flow, but I read cardinals like this so did not have much concern, I am also concened about oxygen in the water, I do not use an air stone, and I wonder if the built in filtration and the water movement created by the intake and return are enough. So what do you all think? Where should I start? Should I start with removing all the decor and giving the gravel a good vacuum and do a water change?

[neilanh]

Here's some information that will hopefully be beneficial to you

Greater Washington Aquatic Plant Association » Algae in the Planted Aquarium

[jsoong]

I think increasing water aeration & flow would be the first thing to try. <After manually removing the worst bits.> BGA cannot thrive in high O2 environment. Personally, I don't think those build in filters are that great for flow, maybe you can throw in an airstone or a power head to improve aeration & flow to the affected area.

[summit]

I am currently treating ich with heat (86F) which I am suspecting why I have this problem in the first place (low o2) and it looks like my amazon sword is not going to make it, so I was thinking, would it be a good idea to do a blackout to kill the BGA? as well as a bit of algae on my driftwood my otto does not seem to want to eat, or will a blackout not effect BGA? would this be good to do on top of increasing flow and o2, I just want to be sure I am rid of this before starting to add the plants I am wanting for long term.

[jsoong]

You can do a blackout as well. But be sure to remove as much of the BGA beforehand. Some species of BGA can release toxins when they die, and people have ran into problems with mass die off of BGA during a blackout. <Same thing when your get "toxic algae" in a lake that kills off all the fish.> To be safe, do a 50% pwc before & after the blackout.

[timwag2001]

here is some info for you to read
Free of algae with Redfield Ratio | Aquariumpagina's van Charles Buddendorf

[summit]

thanks for the info! I am sure that will come in handy, I did a thourough gravel vacuum last night getting rid of all signs of BGA, I also added an airstone, I wonder if it was BGA because it did not have much of an odor, where I heard BGA stinks bad! irregardless, I am going to do one more gravel vac tonight, (because I stirred up the substrate and its debris a bit reworking) things to clean things up, and then do a blackout to kill off the algae, if it comes back I am going to look more closeley into this Redfield ratio, interesting stuff, thank you all.

[SWerner13]

turn your light down as well, 10 hours is a lot of light especially for a low number of low light plants. try closer 6 or 7 hours per day

[WhiteDevil]

6-8 hours per day of light, feed 3 days out of 7.